First rinse your eyes with cool water or saline solution right away for atleast 15 minutes. Note:- Dont rub or squeeze your eyes with your hands. In case you wear contacts, then remove them and continue to wash your eyes.

If you continue to feel uncomfortable, then immediately go to ER room and consult an eye specialist.

In case some household substance like soap or shampoo falls, then all you need is a good rinse and it will suffice.